Aircraft heating system



Sept. 5, 1950 I B. L. MESSINGER AIRCRAFT HEATING SYSTEM 2 Sheets-Sheet 1 Filed Aug. '13, 1946 INVENTOR. BERNARD L. MESSINGER Agent Sept. 5, 1950 B. L. MESSINGER AIRCRAFT HEATING sysmm.

2 Sheets-Sheet 2 Filed Aug. 13, 1946 INVENTOR J BERNARD L. MESSINGER Agent fluid or heat transfer "median? ntvi en Patented Sept. 5, p50

Heat "jexqhf nge de ive new,

removal of frost, sleet, an'dsnewfaecfi alirdraftf' with theheatingbqliiprnnt furi'ct off-*- I heating the'powefplantsnacelles fo'r cola-wager starting. 0

f Varidus heating systems 'h'ave be'n'prebo d n,

I the..past-,:suchas exhaust heated 10w "press e'ai'r] deliveredI-directxto? the cabin, exhaust-heated 'steam or glycol" circulation secondary heat ex changers, electric,' and separate combustion'heat ers: Alla-have various and :sfious drawbacks, such as requiring renormous ducts for; dirfectly heated 4 10 w, pressure air-systems freezing-"in steam, and decomposition of =g1yco1*in" the circular tion systems, excessive? weight, and =p'0wer1 conisu-mption in the generating equipment forfielectrical systems,-;--a nd unreliabilityeof fignition-fiat EAT NGSYSTEM w-mi. df-uerconsump- I tioniinthemcombustion heaters. I

It is accoz di ngly; an" impqrtant objeqtfdftthis ing system wherein aistable low= v i scosity fluid.

i fi eu at h mpe e send m fi ae between exhaust heated prinrlaryheatexchan e rs and secondary heat, ezichangers.,fe 1; heating a air siipplied' .to the, cabin and/0'1"v gfor anti-icing pup,-

poses. ,Su'chj'a system has; the: advantages of fight-weight, compactnes beeause of small ducts, letee ne lin s a at, e ee er W ewe i I I d. Q3'

sinflicient fei"ariti iein and alley heating, It is a further "jmportant', object ,.of thlSviIl iIention-tdprqvide a heatingsys'tegnbf theftype eans' of-aistandby heater, andtem'perat es heatflisx qui d hieatjexehange I duits, :t he return 9 heated cpnduit [5 leading to a standb'y q bus onheater l6 and thence by a A iila at e chan er ;,l8 d an vthe airplane. From Iangepa, return .cpnduit pump 20 .;which1 is: tipnv dasupplyl conduit merely hasj to Over;-

a o s of per aps the system shpwn' 1;

air, carbon dioxide or other stable gases, although I prefer carbon dioxide because of its convenient critical temperature. The use of high pressure air would involve risk of explosions and problems of make-up, and pressure maintenance involving compression ratios of from 75.130 150 at high altitudes if air is drawnirom the atmosphere,.or large volhme reservoins .5 if prelghargedi to the, required pressure, since liquid air could not conveniently be maintained as such to form a sourcei of supply.

When carbon dioxide is used as the circulatihg fluid, the working pressure,i n, the,sy,stem canbe maintained by providing a bott n ofililquidlcanbon dioxide connected to the supply conduit 14 by a pipe 22. The saturation temperature-pres- 4 from the figure, but the layout and piping is duplicated therein; a make-up and pressure regulating carbon dioxide bottle 2| being connected by a pipe 30 leading to each primary heat exchanger lll, this pipe corresponding to the supply conduit 14 of Figure 1 ands'erving as a cross feed line. allows-any. one primary, heat exchanger to be 'supplied from circulating pumps=I-.2B,.=jin either Wing; A pipe 3|, with numerous branches idenz lwtified by the same numeral for convenience in tracing, leads heated fluid to the various secondary heat exohangers strategically located relative pipe 32 similarly connects to the various outlets of the secondary exchangers to return the fluid sure relationship for carbon dioxide enables au- I fihej. bottle is cemmer ialiy available. and n readily be replacedwhen the pressuretherei'n us. o.,s.ystem..-nr ssure- In. order. to control tt e' temperatures. and hen e. the. system ....ur. t. is inserted; a. jacket 23.- having arrangements to circulate air therearound com.-

, insan air inlethorn. 224,? which m y be supdiby. cool" air,from..the 1cabin press llie. system, ant; an jr. outletlii; Hea inhmfians. 25; such. s

@Lelwt ic, coil with suitable controls, serve to eori rolth mperature. of. the; jacket. air. at the siredi point. In} the; event the temperature. of kt: Available. coming. all: exceeds. thed'esiredftemsure o'ffia hondiqxideisnahoht 1;L 0. D....s'. .i.

e se on ry heatexchanger l.8.. mayhav amindir d alelie ric driyenfan ZT for circulatfg'therethroughthe air.- tobeheated, or reliance may be had on the cabin ventilating systemby pr o vidingindividualduots from a central. source :Zfa of" fresh. or. recirculated; air, as, shown. and dc..- scribee, nhmore detail in connection with, the Infototypehe ine, ystem shown,in..-Figure. 2'.

.ce the heating. ystem is. not. necessa y operated at times when heat is not needed. the circulating, pumpzu, can. be; shu down, nd he exhaust: by-pass, valve. 13,. shifted to. by-pass the primary heat exchanger, althoughas carbon. di; .blx'idifsstableup to about3000 F., the then stag,- fn'ant; gas. in, theprimary interchanger. would not be injured. by. long, exposure. to; the temperatures inyolvedinthe engine exhaust/system;

A. de'sirabletemperature.rangerwould be800? inther turniin s; aslwin ndempennaeeanth icing, requires a, minimum. temperature the ,secpn ry ea x han ers of approximately 1 .59? I or; ad quate, heat. transfer.-. and galley "backing, and. h atin eq ir ments are, simplified by, providing. such an, operatin temperature, a

The' schematicdlagram offa prototype airplane must he'atediexchangers ill. in. connection with each power plant, which exchangers arercoupled ,tpgethen inlnaifrallelh Qneawinahaslbeenromitted .ahdin rt gas. with. fir .,extinguishin pr p- 1 ,nerature ,..no harmJs, done. as the; criticalnrese tthe primary, heat exchanger lnandli'flfl yst m' h wn. in Fi ure. 2.?use primary or ex:

watchman-rig pump 2!! which may be duplicatechin the other wing.

The anti-icing heat exchangers |8include the fan, as shown .in=F.igure .11, as .itis ,pneierablatmuse all elosednair. circulating; path. in.- the. wings, and empennage. to. avoid. the. heat losses involvedein heating ambient, ainto, the, temperature of the rccirculatingiain i'n, a-closeclsystem The zQneheatv exchangers (1min. the occupied por,tion,of the-.cabi-mare similarv to those -previ-. ously, described, butdo not haye individual fans as it is convenientltoruse. the normal cabin pres? sunizing andrventilating; arrangements (tor supply auto-a commenduct. 33 from, whichbranch ducts 34" lead to the: several. zone; heaters; f from. which tin-then ducts 3,5; deliyes-and-diffuse the heated airsto-desiredslocationst v a It. will lac-evident, that. conventional heating controls, for; each of thezone; secondary heat: ex+ chan ers can-.; provide: tailored temperatures-to .the orderi-ofi the: occupants as: the: pilots? and. seating1com-partinentsrmay require difierent tern"- neratures .th anqwould berth compartments. Such conventional:- heating controls can beeither dampersy.by pass'mixers as. Shown in connection with the primary heat exchanger, or .thitottle valves: 3-orr the heating fluid supply: subject to eonyentienalrremote or thermostatic controls; Irrthe prototyperaircraft heatingi'systemdiagrammejd irL-E-i-gure 2;: the maximum heating-load in;the-wing? and empenriagesecondary heat eiichangers. on: a closed cycl'e basis, is computed to be 885i000'l3. t: 11; per hour at an out'side temperatflreloff 5'i The'cabin heating load is calculatedtube 2303000 13; t. u; at thesame' tempera ture, and- 3533000 BI t. u. at'65"F. ambient ternpenature at which time no provision foranti-, icingfi'srequired because-the icing-range is above 5 ='FI Acoordingly the' maximum load-on the heating system would lee-approximately 1,115,000 BF. t. u-. at- 5 F.; yetthefluid conduits to handle such high-heat'transier varygfrom one-half to one and one quarter inches size. The heat loss'frorn these conduits is nominal, as they can be: well. insulated at a nominalweight' penalty. Theestimated weight" of" the. entire. heating. systemmf'Figure-Z is. less than 1100 pounds.

tIt will thus be seen that I'have provided, an improved andsimplified high pressure convective fluid heating system capable of. high. heat. trans? fer" and'ilocalized control}. wherein. the. fluid. is automatically maintained'at the desired. operate ing pressure. by controllingthe temperatureof a sourceofsupplyfor make=up..fluid.- Havingr. described..only a typical. form oithe invention,v I. doznotg wishtobe limited to=thespe= cific details, herein. set forth, but-wish. to reserve to; myself any variations or. modifications that may appear to those skilled in the art and/or 7 fall within the scope of the following claims.

Iclaim-as'my invention:

I h 1, Aspace'heating system comprising a closed circulating system charged with carbonldioxide gas, means for heating the gas in said system at at least one point remote from said heating point,

means for circulating the carbon dioxide in said closed system, a high pressure bottle of liquid carbon dioxide connected to said closed. circuit adapted to supply and absorb carbon dioxide gas as the pressure in said closed circuit varies, and

means for maintaining a predetermined'temperature in the liquid carbon dioxide in said bottle whereby to 'predetermine and maintain a pressure in said closed. circuit corresponding to the saturation pressure of the gaseous and liquid carbon dioxide at the predetermined temperature of the liquid carbon dioxide.

2. A space heating system comprising a closed piping circuit including supply and return ducts connecting primary and secondary heat exchangers, means for charging said closed circuit with a stable convection gas, means for circulating said gas in said closed circuit, a container partially filled with the liquid phase of said gas in unrestricted communication with said closed circuit whereby to supply and absorb thegas as the, pressure vin the closed circuit falls and increases respectively, and means for maintaining 'a predetermined temperature in the liquid in said container whereby to predetermine and maintain g the liquid carbon a pressure in said closed circuit corresponding to the saturation pressure of the gas and its liquid phase at the predetermined temperature of the I liquid.v

3. A space heating system comprising a necting primary and'secondary heat exchangers,

' a container of liquid carbon dioxide in unrestrict- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number c Name Date 1,579,314 1 Harrison Apr. 6, 1926 1,844,263 Alex Feb. 9, 1932 1,934,958". White Nov.'l4, 1933, 2,264,297 Clay Dec. 2, 1941 clos ed. circuit including supply and return ducts con- 

